The present disclosure relates to a porous humidity-control tile and a method for manufacturing the porous humidity-control tile, and more particularly, to a porous humidity-control tile having cellular micro-spherical pores uniformly formed in a moisture controllable natural material having nano pores for improving moisture adsorption/desorption ability, and a method of manufacturing the porous humidity-control tile.
Recent buildings are air-tightly insulated for improving heating or cooling efficiency and saving energy; however, this air-tight insulation may cause environmental health problems and make it difficult to control humidity.
About 40% to 70% humidity is proper for human residences. If humidity is higher than the range, mites or mold may increase, and thus allergic diseases such as asthma and atopy may increase due to excrements or harmful fine particles of such living things. On the other hand, humidity lower than the above-mentioned range may cause other problems: for example, virus diseases such as a cold, malfunctioning of precise devices caused by static electricity, fires, and deterioration of works of art.
Therefore, development of humidity-control antibacterial materials is necessary and socially important for preventing contamination of residual environments caused by mold or pathogenic bacteria and keeping residual environments clean.
Generally, humidity-control materials have capillaries on their surfaces so that the humidity-control materials can condense vapor (gas) if humidity is high and evaporate condensed water if humidity is low. Such a humidity-control material is used to maintain the inside humidity of a building or a closed space within a predetermined range according to the external environmental conditions. For this, the humidity-control material has about 3-nm to 7-nm fine pores.
Although artificial materials having chemically formed nano pores are used as building humidity-control materials, such artificial materials are expensive. Therefore, due to economical reasons, natural materials are mainly used as humidity-control materials. Therefore are patents related to natural humidity-control materials.
Korean Patent No. 0495571 (Jun. 6, 2005) discloses “Humidity controlling healthy tile composition and process for the preparation of tile.”
In detail, the 0495571 Patent relates to a health tile including loess, clay, fly ash, diatomite, and crushed glass, and a process for preparing the health tile. The disclosed health tile includes 0 wt % to 30 wt % of natural loess, 30 wt % to 50 wt % of natural clay, 30 wt % to 50 wt % of fly ash, 10 wt % to 30 wt % of diatomite, and 5 wt % to 15 wt % of crushed glass. Moisture adsorption, desorption, and deodorization characteristics of the health tile are explained.
Korean Patent No. 0651080 discloses a humidity-control non-organic composition including: 100 parts by weight of one of silica gel, zeolite, and calcium silicate; 10 to 45 parts by weight of resin binder, 70 to 200 parts by weight of limestone and calcium silicate; and 100 to 200 parts by weight of water.
Japanese Unexamined Patent Application Publication No. H08-144387 discloses a humidity-control building material prepared by hardening a mixture of calcium hydroxide and a composition including allophone or imogolite, and a method for preparing the humidity building material. Besides the above-mentioned patents, there are many patents relating to a humidity-control building tile using zeolite and calcium silicate.
However, humidity-control tiles of the related art are heavy because the humidity-control tiles are formed of a dense material and are large due to current trend of building materials. Therefore, it is necessary to reduce the weight of the humidity-control tiles for convenience in transportation and working.
The weight of such a humidity-control tile can be reduced by forming pores in the humidity-control tile; however, this may reduce the strength of the humidity-control tile. Generally, the weight of a humidity-control tile is reduced by fabricating the humidity-control tile using a pore forming material.
If a chemical foaming agent is used as a pore forming material for fabricating a humidity-control tile, relatively large pores are formed in the humidity-control, and the mechanical characteristics of the humidity-control tile are deteriorated. In an alternative method, polymer sponge is used as a pore forming material for fabricating a porous material.
A brief explanation will now be given on the alternative method. Polymer sponge is placed in ceramic slurry to coat the polymer sponge with the ceramic slurry, and the polymer sponge is compressed to remove excessive ceramic slurry. Then, the polymer sponge is dried and fired to form porous ceramic.
During the firing process, the polymer sponge is removed by thermal decomposition and gasification, and thus pores are formed at places where the polymer sponge is removed.
However, the size of pores formed in the ceramic fabricated using a polymer sponge are relative large at about 200 μm or greater, and since struts located between the pores of the ceramic are also porous, the durability and strength of the ceramic are low.